The present application relates to a monitoring camera for applying an infrared radiation, for example, to a subject to capture an image of the subject.
In general, there have been provided monitoring cameras for capturing images of suspicious objects or suspicious individuals for security against crimes in shops, on streets, in parking lots, and in various other places. Some monitoring cameras are combined with an infrared projector for projecting an infrared radiation to a subject. The infrared projector is installed near the monitoring camera to apply the infrared radiation to an image capturing range of the monitoring camera. The monitoring camera captures an image of the subject which is irradiated with the infrared radiation. Therefore, the monitoring camera combined with the infrared projector is capable of monitoring a subject and recording its image even at night or in a dark environment.
Monitoring cameras with a camera head swingable back and forth and up and down for an enlarged image capturing range are also in use. Such a monitoring camera may also be combined with a plurality of infrared projectors to cover the swinging angle of the camera head for capturing images in a wide image capturing range. Monitoring cameras incorporating a small-size infrared projector have also been provided.
Japanese Patent Laid-open No. 2004-220147 discloses a monitoring camera equipped with an illuminating infrared source.
The traditional monitoring camera with the projector cannot be remotely controlled to adjust its irradiation angle. Therefore, the projector itself needs to have a sufficiently large irradiation range. If the projector is to maintain a radiation flux density required for the monitoring camera to capture a desired image, then the projector is required to have a large output level. However, in order for the projector to have a large output level, the projector has to be large in size. However, it is difficult to have a large-size projector mounted on a monitoring camera having a motor-driven swingable camera head which is subject to size limitations.
If a monitoring camera is combined with a small-size projector mounted on a camera head thereof, then the projector is capable of providing sufficient illuminance only within a short distance because the projector itself is small in size. When a monitoring camera has its zoom lens shifted toward a telephoto end for capturing an image of a subject in a far position, the amount of a radiation applied to the subject tends to be insufficient if the projector has a fixed projection angle. Therefore, the infrared radiation application capability of the projector limits the image capturing range of the monitoring camera.